This invention relates to siloxane modified polyisocyanurates.
Polysiloxanes are a well known class of polymers which are useful as surfactants, elastomers coatings and the like. While these polysiloxanes have found great utility, it is often desirable to provide a harder polysiloxane for certain applications, especially coating applications.
Siloxanes are known additives in the manufacture of polyurethane, polyurea and polyisocyanurate foams. In such foams, the siloxane acts as a smoke suppressant, surfactant and/or cell control agent in the foaming process. Among the siloxanes known for this purpose are hydroxy-terminated siloxanes which react with the isocyanate in the formulation and are therefore incorporated into the polymer chain. However, the siloxane in these foams comprises only a very small fraction (10 percent or less by weight) of the polyols or polyamines used.
Polysiloxanes have also been used as the polyol in a polyurethane formulation. However, since equimolar amounts of polysiloxane polyol and polyisocyanate were used in making the polyurethane, essentially no isocyanurate groups were formed in the reaction. Polysiloxanes have not heretofore been used as the sole or principal component of the active hydrogen-containing material in a polyisocyanurate formulation.